1. Field of the Invention
Apparatuses consistent with the present invention relate to a multiple-input multiple-output (MIMO) antenna operable in a multiband. More particularly, the present invention relates to a MIMO antenna which is provided in a miniaturized size and can operate in a multiband.
2. Description of the Related Art
With the demand for multimedia services of high quality using wireless mobile communication technology, a next-generation wireless transmission technique is required to deliver massive data at a higher rate with a lower error rate.
To respond to this, a multiple-input multiple-output (MIMO) antenna has been suggested. The MIMO antenna carries out the MIMO operation by arranging a plurality of antenna elements in a specific structure. The MIMO antenna makes the overall radiation pattern sharp and transmits the electromagnetic waves farther by combining the ration pattern and the radiation power of the antenna elements.
Accordingly, it is possible to increase the data transfer rate in a specific range or expand the system range for a specific data transfer rate. The MIMO antenna, which is the next-generation mobile communication technique applicable to various mobile terminals and repeaters, is attracting attention as a new solution to overcome the limited transmission quantity of mobile communications.
However, since the MIMO antenna requires smaller antenna elements to mount them in a small terminal, it is hard to implement using a conventional antenna.
Thus, a small antenna element is needed that can implement the MIMO system in accordance with the miniaturization of the terminal.
In the mean time, development of various wireless communication services available using the wireless terminal are under way such as GSM, PSC, WLAN, WiBro, and Bluetooth. A reconfigurable antenna is required to receive the radio communication services using a single wireless terminal.
To this end, an antenna having a very wide frequency band covering a plurality of service bands or a multiband antenna operating in double or multiple frequency bands is under development.
By implementing the MIMO antenna by arranging a plurality of antennas operable in the multiple frequency bands, an antenna can operate in various service bands and can also transmit data efficiently.
However, the size of the antenna operating in the wide frequency band can be reduced, but may face noise and interference caused by the unused band. In the case of the MIMO antenna which arranges the plurality of antennas, this problem can be more serious.
In contrast, the multiband antenna suffers less noise and less interference than the antenna operating in the wide frequency band, but its size is greater than the antenna operating in one band. As a result, when the plurality of the multiband antennas are arranged, the size of the MIMO antenna increases.